Swingman Kyle Snyder and lefty specialist Javy Lopez won the last two available spots.
Right-handers Craig Hansen, Manny Delcarmen and Bryan Corey will start the season at Triple-A Pawtucket.
Mike Timlin is expected to start the season on the disabled list and, if everything goes according to schedule, will be activated for the home opener on April 10 against the Mariners.
That was one of the reasons, according to manager Terry Francona, that Delcarmen did not make the club.
"[He's] a little bit maybe more than just meets the eye," said Francona. "He's somebody, like a Hansen, that we are heavily counting on. We don't know how far into the future. But with Timlin progressing as well as he is and coming back five, six days into the season, we felt like to possibly keep Manny, [that] there's a decent chance he's not going to pitch with the guys we have ahead of him right now. ... We decided to go ahead and send him to Triple-A, let him get started now, so he doesn't lose 10 days."
Delcarmen made 50 appearances for the Red Sox in 2006, going 2-0 with a 5.06 ERA.
Similarly with Hansen, the Red Sox feel he simply needs more time to develop. The Sox rushed him to the Major Leagues in both 2005 and 2006 because of a lack of bullpen depth on the club.
General manager Theo Epstein and Francona now feel the club has enough bullpen arms so that Hansen can take the development steps necessary to become the pitcher the club projected when they selected him in the first round of the 2005 First-Year Player Draft.
"He was very much rushed," Francona said. "But when he was in the Minor Leagues, he was always on a program or a routine. We want him to go down and compete. By his own admission, it's been kind of an up-and-down spring. We're certainly looking for consistency. We still all firmly believe this kid has a very bright future. Now he needs to go show that. I think he's prepared to do that."
Hansen seemed to take the news in stride.
"I kind of had a feeling," said Hansen. "I know I was inconsistent with my outings and that I was hurting the ballclub. They're going to make the right decision for the ballclub. [Francona] basically said to go down there and compete as a reliever and make your way back up here. He said basically, 'I'll see you soon.'"
Corey had a solid camp and couldn't have done anything more to impress Francona and the front office. But he was simply caught in a numbers game.
What Snyder offers the team is the ability to pitch long or middle relief and spot start.
"It's definitely nice to know where you're going," said Snyder. "I couldn't be happier to be part of this organization to start the year off. I'll go start the year and do whatever I can to help this club win. I'll take the ball whenever he gives it to me."
With Lopez making the team, he will be the third lefty behind J.C. Romero and Hideki Okajima.
"I'm pretty happy about it," said Lopez. "It was kind of unexpected knowing that he had two lefties already. It's nice to join the club and try to help them win."
The realistic side of Lopez knows that his days could be numbered with Timlin's return looming.
"Obviously, you hope it's full-time," Lopez said. "Things happen, things change. Just kind of take it for what it's worth. It's an honor to be on the team. If it's for a week, great. If it's for a full season, even better."
The Red Sox position players have been set since the beginning of camp, as the starting nine will be backed up by Wily Mo Pena, Doug Mirabelli, Alex Cora and Eric Hinske.
Ian Browne is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.